Facebook published a blog post on Friday afternoon, explaining a security glitch that caused the email addresses or phone numbers of about 6 million users to have been unintentionally shared. The glitch arose as part of Facebook's efforts to make suggestions on who you might want to add as a Facebook friend.

The company explained the error in detail in the blog post, explaining how that data came to be shared and how the data was used:

"We've concluded that approximately 6 million Facebook users had email addresses or telephone numbers shared. There were other email addresses or telephone numbers included in the downloads, but they were not connected to any Facebook users or even names of individuals. For almost all of the email addresses or telephone numbers impacted, each individual email address or telephone number was only included in a download once or twice. This means, in almost all cases, an email address or telephone number was only exposed to one person. Additionally, no other types of personal or financial information were included and only people on Facebook – not developers or advertisers – have access to the DYI tool."

The company explained that it learned of the error through a report in its White Hat program where it rewards external researchers who discover flaws in Facebook's system.

Facebook wrote in the blog post that the error "allowed some of a person's contact information (email or phone number) to be accessed by people who either had some contact information about that person or some connection to them."